usb: gadget: u_bam: Lock access to port_usb in start/stop transfers
usb: gadget: u_bam: Lock access to port_usb in start/stop transfers

Add protection to access to port_usb fields in start/stop transfers.
Otherwise the functions might compete with disconnect sequence
and null dereference might occur.

Change-Id: I7e62ddd98adc414cadf426daae900c5db04939ee
Signed-off-by: Lena Salman <1fd51afc30cf4384ca4f873323a134889ed11aea@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas